Comparison of the gene expression level of the three clusters, and of peak vs. broad promoters. Gene expression level (A) in the three clusters and (B) in the single peak and broad groups of the clustered promoters. The y-axis shows the gene expression level (GEL) in units of tags per million (tpm) in log-scale for visibility reasons, a pseudo count of 1 tpm was added to each promoter to avoid logarithm of zero. The comparisons of GEL are highly significant for both tests, between the three clusters (Kruskal-Wallis test, p-value = 1.05E-10) as well as between the single peak and broad class (Wilcoxon rank-sum test, p-value = 5.5E-15).
Kratz et al. BMC Genomics 2010 11:257 doi:10.1186/1471-2164-11-257